The RNA Synthesis and Recombinant Protein Core is a shared facility which will provide reagents to facilitate the studies proposed; the Recombinant Protein Production Facility will provide reagents. In order to facilitate the experiments proposed, milligram amounts of pure recombinant RNA encompassing the RT-U5-PBS region of HIV-1 genomes and synthetic tRNA will be needed. To provide this service, the Core will express and purify recombinant T7 DNA dependent RNA polymerase (T7 polymerase), purify recombinant plasmids and perform in vitro tran- scriptions. An oligonucleotide synthesizer is requested to generate specifically modified RNAs and DNA templates and primers. The Core will provide recombinant reverse transcriptase (RT) and nucleocapsid (NCp7) proteins. The concentration of these activities in a shared resource complex will enable these reagents to be derived in an efficient and cost effect manner and will capitalize on the available experimental expertise in this area.